Matrix for stump legs



J. F. ROWLEY. MATRIX FOR STUMP LEGS. APPLICATION FILED MAR. 28, I921.

Patented Jan. 31, 1922.

stares @FFEQ JAMES F. BOWLEY, OF CHICAGO, ILLINOIS.

MATRIX ron STUMP LEGS.

To all whom it may con-0cm..-

Be it known that 1, JAMES F. RoWLEY, a citizen of the United States of America, and a resident of Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Matrices for Stump Legs, of which the following is a specification.

This invention relates mainly to a new method of taking an impression of a stump by utilizing the weight of the patient to at tain the pressure required and inthe right direction for forming a matrix corresponding to the walking'shape of the stump leg. T-leretofore it has been customary to form the matrix by placing plastic material around the stump and, therefore, the matrix did not correspondto the walking form, and made necessary building up the cast taken from the matrix at points correspond ing to the sensitive parts of the stump leg so as to relieve these parts of the leg from pressure when in the socket. A wholly accurate and comfortable fit was impossible by such methods. The present invention relates to the discovery that if the matrix is made when the surfaces of the stump leg are under pressure as produced by the patients weight, the soft parts of the stump are displaced upwardly longitudinally of the stump le to exactly the form assumed under walking conditions. This method overcomes the errors of prior systems of mak: ing artificial legs from measurements which depended strongly on guess work as to just what to do and what not to do in the way of building up or cutting away parts of the cast on which the socket is formed.

The objects of the invention may be attained by the use of a structure such as illustrated in the drawings, wherein Figure 1 illustrates a suspended matrix receiving an impression.

Fig. 2 is a fragmentary plan view of the matrix.

Prior systems of fitting stump legs include such as are based on the use of templates made from measurements so that an approximate fitting might be had in a socket carefully made in keeping witha template. However, sockets made by this method by the best workmen seldom attain the finest detail which makes a comfortable fitting artificial leg. The customary method of forming a plaster Paris cast results in a cast accurately representing the formation Specification of Letters Patent.

. Patented Jan. 31, 1922.

1921. Serial No. 456,270.

of the stump when in repose, but does not correspond with the real formation when the soft part or flesh is displaced by putting ones weight on the bearing portions of the stump leg, and this method of making sockets invariably required a reduction in size of the cast by cutting it down or scraping it and by pasting on pieces of leather to make more room for bones in the socket. By means of the present method, the matrix bemg formed with nearly or quite the weight of the patient on the matrix, the matrix when filled with plaster Paris produces a cast which is identical in form with the stump leg when in use. A wax socket reinforcement is built over this cast and afterward carefully fitted into the top of the artificial leg with the result that the socket is invariably a comfortable fit.

In carrying the present method into effect, use is made of a matrix of suitable length'which has been laced to substantially the diameter of the stump leg. This matrix is made of one layer of light material such as cordovan and is more or less saturated with a wax-like material and previous to the fitting of the matrix is warmed so as to become freely pliable and soft. This matrix is suspended by means of cords as illustrated in Figure 1 of the drawing. The ends of the cords are tied to the matrix by passing the same through eyes 2 in the ears 3 formed at the sides of the upper end of the matrix 1. These ears are preferably backed by metal plates 4: in order to hold the eyes 2 properly spaced. The upper ends of the cords 5 may be attached to any suitable support such as the backs of two chairs. While the matrix is warm, the patient makes the impression as desired by lowering the stump leg into the matrix and placing more or less of his weight thereon. This causes the stump leg to assume its walking shape, the soft parts of the stump being pushed upwardly by the pressure applied in the matrix. Since the matrix yields readily under the pressure, it

assumes the walking shape of the stump leg.

The matrix becomes rigid when its temperature is reduced to normal. The plaster cast may then be made which without building up is suitable for use in forming the socket which is finally fitted to the artificial limb.

Although but one specific embodiment of this invention has been herein shown and described it will be understood that numerous details of the construction shown may be hollow cylindrical body formed of a. layer I of flexible material like leather affording tensile strength in combination with a substance rendering the'structure plastic only 10 when warmed.

Signed at Chicago this 25th day of March,

' JAMES F. ROWLEY. 

